The specific technical objectives of this Phase I proposal are: To evaluate the signal quality of two new electrode technologies. 1) Physiometrix Inc. Hydro-dot TM electrodes, which consists of a Silver- Silver Chloride gel, and 2) new active, prepless, dry electrode technology developed by IBT (Integrated Biosensing Technology). These are to be compared to standard cup electrodes with conductive paste. The key issues to be answered by evaluating these electrode technologies are 1) ease of electrode application by ICU nurses; 2) signal integrity (i.e., signal to noise ratio, recording stability over extended periods). To develop a headset for continuous EEG recordings which can be applied by a nurse or minimally trained health care professional. The cap will be modified to accommodate both new electrode types. This will allow for a comparison study to determine which cap configuration can be most reliably applied by minimally trained individuals. Key issues to be answered for ICU nurses and c) ability of ICU nurses to train other nurses. To develop an integrated system which utilizes the TEMEC compact battery powered physiologic data recorder, with a radio transmitter device to provide wireless data transmission. This integrated system will attach to the EEG headset that holds the electrodes on the head. The combined system will allow for the EEG data to be transmitted to a base station where the data can be displayed and analyzed. Key issues to be addressed are: 1) selection of the appropriate wireless LAN technology which ensures: a) Immunity to interference from outside sources; b) Immunity from multipath interference; c) Total network capacity; d) Network salability; and e) Performance consistency. 2) Limitations of battery performance will be based on the TEMEC system for Phase I. If improvements are needed they will be implemented as part of the Phase II effort. Long term wireless recordings are not part of the Phase I effort. Develop display software and algorithms for data reduction and review. Key issues to be addressed are the development of a display package capable of performing in a real time environment. The selection and development of EEG analysis algorithms is not an objective to be fulfilled in Phase I.